Production of allylic ethers

ABSTRACT

A LIQUID PHASE PROCESS FOR THE PRODUCTION OF ALLYLIC ETHERS COMPRISING ADMIXING AN ALLYLIC ALCOHOL HAVING THE FOLLOWING STRUCTURAL FORMULA:   R1-CH=CH-CH(-OH)-R2   WHEREIN R1 AND R2 ARE ALKYL RADICALS, STRAIGHT OR BRANCHED CHAIN, HAVING 1 TO 7 CARBON ATOMS, CYCLOALKYL RADICALS HAVING 4 TO 10 CARBON ATOMS, ARYL RADICALS HAVING 1 TO 2 BENZENE RINGS, OR ALKYLENE PORTIONS OF AN ALICYCLIC RING, EACH PORTION HAVING 1 TO 3 CARBON ATOMS, AND FROM ZERO TO SIX MOLS PER MOL OF THE ALLYLIC ALCOHOL OF AN ALCOHOL HAVING THE FOLLOWING STRUCTURAL FORMULA:   R3(OR4)NOH   WHEREIN R3 IS AN ALKYL OR ALKENYL RADICAL, STRAIGHT OR BRANCHED CHAIN OR CYCLIC, HAVING 1 TO 20 CARBON ATOMS; R4 IS AN ALKYLENE RADICAL, STRAIGHT OR BRANCHED CHAIN, HAVING 2 TO 10 CARBON ATOMS; AND N IS ZERO OR, PROVIDED R3 IS AN ALKYL RADICAL, AN INTEGER FROM 1 TO 100, IN THE PRESENCE OF AN EFFECTIVE AMOUNT OF A CATALYST CONSISTING ESSENTIALLY OF A MOLYBDENUM-OXYGEN COMPLEX WHEREIN THE MOLYBDENUM IS IN THE OXIDATION STATES OF +4, +5, OR +6, OR MIXTURES THEREOF, AND AT LEAST 10 MOL PERCENT OF THE MOLYBDENUM IS IN THE +5 OXIDATION STATE AND AT A TEMPERATURE SUFFICIENTLY HIGH FOR A REACTION TO TAKE PLACE.

United States Patent ifice 3,781,368 Patented Dec. 25, 1973 ABSTRACT OF THE DISCLOSURE A liquid phase process for the production of allylic ethers comprising admixing an allylic alcohol having the following structural formula:

R1CH=CH H-Rg wherein R and R are alkyl radicals, straight or branched chain, having 1 to 7 carbon atoms, cycloalkyl radicals having 4 to 10 carbon atoms, aryl radicals having 1 to 2 benzene rings, or alkylene portions of an alicyclic ring, each portion having 1 to 3 carbon atoms, and from zero to six mols per mol of the allylic alcohol of an alcohol having the following structural formula:

wherein R is an alkyl or alkenyl radical, straight or branched chain or cyclic, having 1 to 20 carbon atoms; R, is an alkylene radical, straight or branched chain, having 2 to 10 carbon atoms; and n is zero or, provided R is an alkyl radical, an integer from 1 to 100, in the presence of an elfective amount of a catalyst consisting essentially of a molybdenum-oxygen complex wherein the molybdenum is in the oxidation states of +4, +5, or +6, or mixtures thereof, and at least 10 mol percent of the molybdenum is in the +5 oxidation state and at a temperature sufiiciently high for a reaction to take place.

FIELD OF THE INVENTION This invention relates to a process for the production of allylic ethers; and, more particularly, to a process for producing allylic ethers using an oxymolybdenum catalyst.

DESCRIPTION OF THE PRIOR ART Allylic ethers are well known intermediates in the chemical industry for the production of glycidyl ethers, silicone containing surfactants and various copolymers and terpolymers derived in part from olefin monomers. The production of these allylic ethers by the autoxidation of olefins, however, is not feasible in that it leads to the formation of allylic hydroperoxides or their decomposition products together with products of oxidation of the double bond and, in general, fails to elfect a selective reaction at the allylic position to introduce alkoxy groups. To overcome the problems raised by autoxidation, various catalytic condensation processes of allylic alcohols with themselves or other alcohols have been proposed using mineral acids, platinum or copper catalysts; however, the cost and convenience of operation together with selectivity have not been commercially satisfactory.

SUMMARY OF THE INVENTION An object of this invention, therefore, is to provide a one-step catalytic condensation process for the production of allylic ethers which is highly selective and reduces the cost of operation while increasing the convenience of operation.

Other objects and advantages will become apparent hereinafter.

According to the present invention, such a one-step process for the production of allylic ethers has been discovered comprising, admixing, in the liquid phase, an allylic alcohol having the following structural formula:

wherein R and R are alkyl radicals, straight or branched chain, having 1 to 7 carbon atoms, cycloalkyl radicals having 4 to 10 carbon atoms, aryl radicals having 1 or 2 benzene rings, or alkylene portions of an alicyclic ring, each portion having 1 to 3 carbon atoms, and from zero to six mols per mol of the allylic alcohol of a nucleophilic alcohol having the following structural formula:

wherein R is an alkyl or alkenyl radical, straight or branched chain or cyclic, having 1 to 20 carbon atoms; R, is an alkylene radical, straight or branched chain, having 2 to 10 carbon atoms; and n is zero or, provided R is an alkyl radical, an integer from 1 to 100, in the presence of an elfective amount of a catalyst consisting essentially of a molybdenlm-oxygen complex wherein the molybdenum is in the oxidation states of +4, +5, or +6, or mixtures thereof, and at least 10 mol percent of the molybdenum is in the +5 oxidation state.

DESCRIPTION OF THE PREFERRED EMBODIMENT The process can be carried out by introducing an allylic alcohol, optionally a second alcohol as defined above, and an oxymolybdenum catalyst into a reaction vessel.

The reaction vessel can be glass, glass-lined, aluminum, titanium or stainless steel. A glass-lined polytetrafluoroethylene coated stainless steel autoclave is found to be advantageous. A tubular reactor made of similar materials can also be used together with multipoint injection to maintain a particular ratio of reactants.

Some form of agitation is preferred to avoid a static system and can be accomplished by using a mechanically stirred autoclave, a multi-point injection system, or a loop reactor wherein the reactants are force circulated through the system. Sparging can also be used. It should be pointed out that agitation is inherent where the process is carried out in a continuous manner although the various modes suggested further enhance the homogeneity of the liquid reactants therein.

As set forth above, the allylic alcohol has the following structural formula:

OH lM-CH OH-OH-Rz wherein R and R are alkyl radicals, straight or branched chain, having 1 to 7 carbon atoms, cycloalkyl radicals having 4 to 10 carbon atoms, aryl radicals having 1 or 2 benzene rings, or alkylene portions of an alicyclic ring, each portion having 1 to 3 carbon. atoms. Substituted radicals are contemplated and the substituents can in clude a wide variety of radicals containing carbon, hydrogen, oxygen, nitrogen, and halogen. Examples of substituents are aryl, halogen, ester, ether, ketone, nitrile, and amide radicals. The substituents are preferably limited to no more than two to each radical and each contain, preferably, no more than six carbons. The allylic alcohols are exemplified as follows: Z-cyclohexenol, Z-cycloheptenol, 2-cyclopentenol, 2-hexene-4-ol, 2-heptene-4-ol, 2-pentene-4-ol, 3-hexene-5-ol, 3-heptene-5-ol, 4-heptene-6- ol, 5-octene-7-ol, 4-octene-6-ol, 2,5-dimethyl-2-hexene-4- ol, l-phenyl-l-butene-S-ol, l-cyclohexyl-l-butene-S-ol,

methyl 8- or ll-hydroxypalmitoleate, 8- or ll-hydroxyoleamide, 1methyl-3-hydroxycyclohexene, and 8-chloro- 3-hydroxy-2-octene. It should be noted that simple autoxidation mixtures of olefins will yield useful allylic alcohols.

According to the process of the invention described herein the above allylic alcohols will condense with themselves to form his ethers. In like fashion, the allylic alcohols will condense with what can be described as a nucleophilic alcohol to form a wide variety of allylic ethers. Using the same process conditions, the aforementioned bis ethers will undergo transetherification when reacted with an allylic alcohol or a nucleophilic alcohol. It is interesting to note that the transetherification is often accompanied by condensation reactions involving the allylic alcohol liberated by the transetherification. To essentially avoid the condensation reaction and the attendant production of water, the use of less than stoichiometric quantities of allylic or nucleophilic alcohol is suggested. In such a reaction the molar ratios of allylic or nucleophilic alcohol to bis ether can be the same as those molar ratios for nucleophilic alcohol to allylic alcohol set forth below. The transetherification feature lends versatility to the instant process.

Although it is preferred to use the bis ethers in the transetherification, unsymmetrical diethers can also be used in like ratios. In this case, the R and R radicals in one moiety would differ from at least one of the corresponding radicals in the moiety on the other side of the oxygen bridge. The definition of the diether, which includes the bis ether, is as follows:

wherein R R R and R are alike or different, but can be defined as for R and R above.

The nucleophilic alcohol has been defined above as an alcohol having the following structural formula:

wherein R is an alkyl or alkenyl radical, straight or branched chain or cyclic, having 1 to 20 carbon atoms; R, is an alkylene radical, straight or branched chain, having 2 to 10 carbon atoms; and n is zero or, provided R is an alkyl radical, an integer from 1 to 100. When the nucleophilic alcohol is admixed with the defined allylic alcohol in the presence of the oxymolybdenum catalyst, the formation of the his ether is essentially suppressed and a mixed ether is formed.

The R and R radicals can also be substituted with aryl, halogen, ester, ether, ketone, nitrile, or amide radicals. The substituents, preferably, are limited, however, to no more than two to each radical, and contain no more than six carbons. Acid groups should be avoided in either alcohol, however, and it may be well to define the useful substituents for the R R R and R, radicals as those inert to the condensation or transetherification reactions.

Examples of useful nucleophilic alcohols are as follows: n-propyl alcohol, n-butyl alcohol, isobutyl alcohol, t-butyl alcohol, n-amyl alcohol, isoamyl alcohol, t-amyl alcohol, neopentyl alcohol, n-hexyl alcohol, n-octyl alcohol, n-decyl alcohol, ethylene glycol monomethyl eth'er, diethylene glycol monoethyl ether, allyl alcohol, Z-ethylhexanol, 3-hexanol, 2-butene-l-ol, 1-butene-3-ol, oleyl alcohol, methyl alcohol, ethyl alcohol, benzyl alcohol, propylene chlorohydrin, 4 hydroxy-butanoamide, cyclohexanol, cyclobutanol, and bis-2-hydroxylethylphthalate.

The catalyst has been defined above as consisting essentially of a molybdenum-oxygen complex wherein the molybdenum is in the oxidation states of +4, +5, or +6, or mixtures thereof, and at least 10 mol percent of the molybdenum is in the +5 oxidation state. The complex must be sufi'iciently soluble in the reaction mixture to the extent that at least l 10- mol of catalyst complex per mol of allylic alcohol is present in the solubilized state. The catalyst can be added in any form, e.g., organic compound, inorganic salt, or complex, providing the defined complex is present in the reaction mixture. A solution containing the desired complex or a compound which will form the complex in situ can be used effectively. A preferred range for the amount of catalyst complex is about 0.5x l0 mol to about 0.5 l0 mol of catalyst complex per mol of allylic alcohol. Higher amounts of catalyst complex can be present in the solubilized state, but no advantage is observed. A preferred catalyst compound is molybdenyl acetylacetonate since it forms the catalyst complex directly in the reaction mixture. Other useful catalyst compounds and complexes are as follows: molybdenum blue, dihydrodioxalatotrioxomolybdate (VI), molybdenyl ammonium oxalate, molybdenyl monochloride hydrate, ammonium molybdate, and molybdenum (V) acetylacetonate. It should be noted that the lower amounts of catalyst complex, i.e., less than O.5 10 mol per mol of allylic alcohol, do not give consistent results ostensibly because of the other prevailing conditions. Therefore, the use of an effective amount of catalyst is a more meaningful definition and can easily be arrived at by the technician.

In the reaction which involves the allylic alcohol and the nucleophilic alcohol, the amount of the latter which can be used can range from about 0.20 mol to about 10 mols of nucleophilic alcohol per mol of allylic alcohol and is preferably in the range of about 0.40 mol to about 6 mols of nucleophilic alcohol per mol of allylic alcohol. The preferred range for transetherification is about one mol to about 4 mols of allylic or nucleophilic alcohol per mol of bis ether. Greater amounts of nucleophilic alcohol can be used, but this serves no practical purpose. Less than stoichiometric quantities of nucleophilic alcohol may be especially advantageous to insure complete reaction of the nucleophilic alcohol, e.g., in the capping of polyols.

It is not necessary to use a solvent, but the use of same is both advantageous and preferred. Any conventional organic solvent which is inert with respect to the reactants and the catalyst complex can be used. Various, aliphatic, cycloaliphatic, and aromatic solvents are useful such as benzene, o-dichlorobenzene, cyclohexane, o-xylene, methyl cyclohexane, chlorobenzene, toluene, decane, cyclooctaine, Tetralin, and Decalin. The amount of solvent can range from about 1 mol or even less to about 25 mols of solvent per mol of allylic alcohol and is preferably about 2 mols to about 15 mols of solvent per mol or allylic alcohol.

Ratios can be kept constant by the use of a continuous process and by analyzing the outlet ratio and adjusting the feed ratio. In a backmixed reactor, the feed is adjusted until the outlet ratio is within the prescribed range. Where two or more reactors are used in series or the reactor is tubular with multi-point injection, the reaction taking place are considered to be a series of batch reactions and are carefully monitored to insure that the molar ratio in any one reaction is not permitted to go below or rise above the prescribed range.

The temperature must be sufficient for the reaction to take place and is primarily dependent on the materials involved. Generally, in order to form active catalyst in situ, temperatures of at least 50 C. are necessary. Where active catalyst is introduced from external sources, temperatures as low as room temperature can be used. In practice, reflux temperatures are most commonly utilized. In cases other than those of reflux temperatures, higher temperatures, such as those above C., can be used temperature sufficiently high for a reaction to take place, and wherein all of the aforementioned radicals and portions are unsubstituted.

2. The process of claim 1 wherein the temperature is the reflux temperature of the admixture.

3. The process of claim 1 wherein the amount of catalyst present is at least 1 10- mol of catalyst per mol of allylic alcohol.

4. The process of claim 3 wherein the amount of catalyst present is in the range of about 0.5 10 mol to about 05x10" mol of catalyst per mol of allylic alcohol.

5. The process of claim 1 wherein the amount of nucleophilic alcohol is in the range of about 0.20 mol to about mols of nucleophilic alcohol per mol of allylic alcohol.

6. The process of claim 4 wherein the amount of nucleophilic alcohol is in the range of about 0.40 mol to about 6 mols of nucleophilic alcohol per mol of allylic alcohol.

7. The process of claim 6 wherein the catalyst is molybdenyl acetylacetonate.

8. The process of claim 1 wherein an organic solvent which is inert with respect to the reactants and catalyst is present.

9. The process of claim 8 wherein the amount of solvent is in the range of about 1 mol to about mols of solvent per mol of allylic alcohol.

10. The process of claim 1 wherein the sole reactant is the allylic alcohol.

11. The process of claim 6 wherein an organic solvent which is inert with respect to the reactants and catalyst is present.

12. A process for transetherification comprising admixing, in the liquid phase, a diallylic ether having the following structural formula:

wherein R R R and R can be alike or different and are straight or branched'chain alkyl radicals having 1 to 7 carbon atoms, cycloalkyl radicals having 4 to 10 carbon atoms, aryl radicals having 1 benzene ring, or alkylene portions of an alicyclic ring, each portion having 1 to 3 carbon atoms, and about 0.20 mol to about 10 mols per mol of diallylic ether of a nucleophilic alcohol having the following structural formula:

wherein R is an alkyl or alkenyl radical, straight or branched chain or cyclic, having 1 to 20 carbon atoms; R, is an alkylene radical, straight or branched chain, having 2 to 10 carbon atoms; and n is zero or, provided R is an alkyl radical, an integer from 1 to 100, in the presence of an effective amount of a catalyst selected from the group consisting of molybdenum blue, dihydro- 10 dioxalatotrioxomolybdate (VI), molybdenyl ammonium oxalate, molybdenyl monochloride hydrate, ammonium molybdate, molybdenum (V) acetylacetonate, and molybdenyl acetylacetonate, and mixtures thereof, and at a temperature sufficiently high for a reaction to take place, and wherein all of the aforementioned radicals and portions are unsubstituted.

13. A process for transetherification comprising admixing, in the liquid phase, a diallylic ether having the following structural formula:

wherein R R R and R can be alike or different and are straight or branched chain alkyl radicals having 1 to 7 carbon atoms, cycloalkyl radicals having 4 to 10 carbon atoms, aryl radicals having 1 benzene ring, or alkylene portions of an alicyclic ring, each portion having 1 to 3 carbon atoms, and about 0.20 mol to about 10 mols per mol of the diallylic ether of an allylic alcohol having the following structural formula:

wherein R and R are as defined above in the presence of an effective amount of a catalyst selected from the group consisting of molybdenum blue, dihydrodioxalatotrioxomolybdate (VI), molybdenyl ammonium oxalate, molybdenyl monochloride hydrate, ammonium molybdate, molybdenum (V) acetylacetonate, and molybdenyl acetylacetonate, and mixtures thereof, and at a temperature sufliciently high for the reaction to take place, and wherein all of the aforementioned radicals and portions are unsubstituted.

14. The process of claim 12 wherein the diallylic ether is a bis ether.

15. The process of claim 14 wherein the catalyst is molybdenyl acetylacetonate.

16. The process of claim 13 wherein the diallylic ether is a bis ether.

17. The process of claim 16 wherein the catalyst is molybdenyl acetylacetonate.

References Cited UNITED STATES PATENTS 2,591,493 4/1952 Arnold et al. 260614 R X 2,847,477 8/ 1958 Watanable et al. 260614 R X 2,847,478 8/1958 Hwa et a1 260614 R X BERNARD HELFIN, Primary Examiner US. Cl. X.R.

260615 R, 614 R, 611 A, 410.6, 404, 475 R, 561 R mg a UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,781,368 Dated- December 25, 1973' Inventor() R. S. Neale It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In claim 1 at line 13, change "R(OR OH" to R (0R Signed and sealed this17th day of September 1974.

(SEAL) Attest: I

McCOY M. GIBSON JR. C. MARSHALL DANN Arresting Officer Commissioner of Patents 

